EP0293981A2 - Processes for the manufacture of superconducting inorganic compounds and the products of such processes - Google Patents

Processes for the manufacture of superconducting inorganic compounds and the products of such processes Download PDF

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Publication number
EP0293981A2
EP0293981A2 EP88201071A EP88201071A EP0293981A2 EP 0293981 A2 EP0293981 A2 EP 0293981A2 EP 88201071 A EP88201071 A EP 88201071A EP 88201071 A EP88201071 A EP 88201071A EP 0293981 A2 EP0293981 A2 EP 0293981A2
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EP
European Patent Office
Prior art keywords
substrate
inorganic compound
superconducting
particles
suspension
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP88201071A
Other languages
German (de)
French (fr)
Other versions
EP0293981A3 (en
Inventor
Antony Clifford Barber
Francis John Vernon Farmer
Peter Charles Steele Hayfield
Ian Robert Scholes
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Timet UK Ltd
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IMI Titanium Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB878713121A external-priority patent/GB8713121D0/en
Priority claimed from GB878713122A external-priority patent/GB8713122D0/en
Application filed by IMI Titanium Ltd filed Critical IMI Titanium Ltd
Publication of EP0293981A2 publication Critical patent/EP0293981A2/en
Publication of EP0293981A3 publication Critical patent/EP0293981A3/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/01—Manufacture or treatment
    • H10N60/0268—Manufacture or treatment of devices comprising copper oxide
    • H10N60/0296—Processes for depositing or forming copper oxide superconductor layers
    • H10N60/0324—Processes for depositing or forming copper oxide superconductor layers from a solution
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/01—Manufacture or treatment
    • H10N60/0268—Manufacture or treatment of devices comprising copper oxide
    • H10N60/0296—Processes for depositing or forming copper oxide superconductor layers
    • H10N60/0352—Processes for depositing or forming copper oxide superconductor layers from a suspension or slurry, e.g. screen printing or doctor blade casting
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/01—Manufacture or treatment
    • H10N60/0268—Manufacture or treatment of devices comprising copper oxide
    • H10N60/0296—Processes for depositing or forming copper oxide superconductor layers
    • H10N60/0576—Processes for depositing or forming copper oxide superconductor layers characterised by the substrate
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/01—Manufacture or treatment
    • H10N60/0268—Manufacture or treatment of devices comprising copper oxide
    • H10N60/0661—Processes performed after copper oxide formation, e.g. patterning
    • H10N60/0716—Passivating

Definitions

  • This invention relates to processes for the manufacture of superconducting inorganic compounds and the products of such processes.
  • a process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, depositing on said surface particles of a superconducting inorganic compound from a suspension of such particles by electrophoresis.
  • the superconducting inorganic compound may subsequently be covered with a resin or varnish or a metal layer such as copper or silver may be deposited thereon.
  • a resin or varnish or a metal layer such as copper or silver may be deposited thereon.
  • pure copper may be deposited and then coated by a resin or varnish.
  • pure copper may be deposited on the superconducting inorganic compound, and the product together with its substrate may then be inserted into a copper or copper alloy cannister, which is subsequently extruded into filaments.
  • a substance which acts as a barrier to substantially prevent further diffusion from the metal layer during subsequent processing may be placed upon the superconducting inorganic compound prior to deposition of the metal layer.
  • the superconducting inorganic compound is typically an oxide of the form A w B x O y where A and B represent elements of which at least one is a metallic element and the subscripts w x and y are numerals denoting the empirical atomic proportions of the compound conducting oxide. There may be additional metallic elements eg. C z etc present in the compound conducting oxide.
  • Such compound conducting oxides may be of the form ABO3, ABO4 or A2BO4 or A2BO (4-y) .
  • Typical elements involved in the formation of these superconducting oxides are yttrium, barium, bismuth, lanthanum, strontium and copper.
  • the present invention is not limited to these elements: the yttrium may be replaced by other rare earth elements, the barium by other alkali elements, and the entire compound may not be a cuprate, but a bismuthate or other compound.
  • the deposited layer will be in a combined rather than elemental state, and typically would be an oxide.
  • the metallic layer which could be copper or a copper alloy, may be deposited immediately following the removal of unattached suspension or contaminants eg. by washing or other cleaning process, from the oxide coated substrate.
  • the substrate is typically an electrically conducting material such as a metal eg. silver, copper or a copper alloy, or molybdenum or titanium or an alloy of one of these. It may be coated by a barrier film prior to the deposition stage.
  • a metallic layer may be deposited after an intermediate treatment such as a heat-treatment of the coated substrate.
  • a process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, depositing on said surface particles of a plurality of different compounds such as oxides or carbonates or a mixture of oxides and carbonates from a suspension of such particles by electrophoresis.
  • Such compounds may include organo-metallic substances.
  • the deposit may subsequently be covered with a resin or varnish or a metal layer may be deposited thereon.
  • a resin or varnish For example, pure copper may be deposited and then coated by a resin or varnish.
  • pure copper may be deposited on the existing deposit, and the resulting product together with its substrate inserted into a copper or copper alloy cannister, which is subsequently extruded into filaments.
  • a substance which acts as a barrier to substantially prevent further diffusion from the metallayer during subsequent processing may be placed upon the existing deposit prior to deposition of the metal layer.
  • the oxide/carbonate coated substrate may be heat-treated in an oxidising atmosphere at elevated temperatures sufficient to cause said particles to chemically react together to form a superconducting inorganic compound.
  • the oxides and/or carbonates will typically include at least one metallic compound.
  • the oxide/carbonate coated substrate could be cleaned in a manner referred to above prior to the heat treatment.
  • the substrate may be metallic eg. silver, gold, titanium, copper or molybdenum or it may be an electrically conducting ceramic or a carbon-containing substance.
  • the substrate may be silver-coated or platinum-coated.
  • the substrate may be fully dense or it may be porous.
  • the substrate may be copper cored.
  • the substrate may be in the form of a strip, tape or wire, tube, plate or disc.
  • the surface of the substrate may be plane, curved, corrugated or stepped.
  • the substrate may be a wire with multiple re-entrant portions eg. star-shaped when viewed in cross-section.
  • the substrate may be a substantially plane disc with micro-grooves on its surface.
  • the oxide-coated substrate may be mechanically worked eg. by drawing, extruding or rolling, so as to consolidate the superconducting compound. Such mechanical working may take place at ambient temperature or at an elevated temperature.
  • the material may also be subject to heat treatment. Further mechanical working and heat treatment may also be necessary.
  • a bundle of strips, tapes or wires so formed may then be bundled together in an evacuated metallic cannister eg. of copper or copper alloy or silver-coated copper or alloy, and such container and its contents co-extruded or drawn in multiple stages to produce a fine elongate product containing a plurality of filaments of conducting oxide material.
  • An oxygen-evolving compound or substance eg. silver oxide may be incorporated with the bundle of strips etc on their admission to the cannister.
  • An electromagnetic field eg a magnetic field, may be applied during the electrophoretic deposition stage to encourage the deposited particles to take up a particular orientation.
  • fibrous particles such as ceramic fibres, alumina or zirconia fibres or silicon carbide fibres may be incorporated into the suspension and electrophoretically deposited onto the surface of the substrate.
  • the particles being deposited may be substantially rounded, or may be acicular or platelet-type in shape. Sizes of particles deposited are typically up to a few microns in size, but larger sizes can be accommodated by attention to the viscosity of the electrophoreting bath.
  • the roughening of the surface of the substrate may be carried out by etching eg. with copper by ammonium persulphate and/or ferric sulphate, or in the case of molybdenum by pickling in hydrochloric acid.
  • the suspension may be dispersed in an electrolyte which includes nitromethane and isopropyl alcohol and possibly additionally zein and aluminium nitrate as necessary for efficient electrophoresis.
  • an electrolyte which includes nitromethane and isopropyl alcohol and possibly additionally zein and aluminium nitrate as necessary for efficient electrophoresis.
  • a process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, applying a fluid coating onto said surface, the coating comprising a plurality of components in suspension and/or in solution in a liquid medium.
  • Said components may comprise metallic compounds such as a chloride, sulphate or nitrate or a citrate, acetate and other salts.
  • the coated substrate is typically heated to a temperature sufficient to cause decomposition of said components and the formation of a surface film of superconducting inorganic compound incorporating each of the elements present.
  • a plurality of successive coatings may be applied, each of said successive coatings containing identical components, or at least some of each of said successive coatings containing differing components.
  • a solution may comprise metal compounds dissolved in an organic base, such as so-called “organo-metallic paints”.
  • a process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, applying a coating on the said surface, the coating comprising a suspension of particles of a superconducting inorganic compound suspended in a liquid medium. Successive coatings may be built up one upon the other.
  • the coated substrate may then be given a heat treatment in e.g. an oxygen-containing atmosphere such as pure oxygen at atmospheric, sub-atmospheric or elevated pressure.
  • the average particle size of the superconducting inorganic compound may be less than one micron.
  • a drying step may be incorporated into the processes according to the invention following the application of the or each coating. Such drying step may be carried out in air and is completed when the liquid medium is substantially evaporated.
  • Relatively volatile dispersion medium is typically selected for example an alcohol.
  • heating may take place in an oxygen containing atmosphere. Heating is typically carried out between a temperature of 400-500°C.
  • the coating may be applied to a cool substrate which is then heated to change the deposit to the desired composition.
  • the coating can wholly or in part be applied eg. by spraying, onto a heated substrate so as to effect decompositioned changes at a fast and homogeneous rate.
  • each such coating may in turn be dried to remove the liquid medium before the application of the next coating.
  • the superconducting inorganic compound may subsequently be covered with a resin or varnish or a metal layer may be deposited thereon.
  • pure copper may be deposited, or silver deposited by thermal decomposition technique, and the copper or silver then coated by a resin or varnish.
  • pure copper may be deposited on the superconducting inorganic compound, and together with its substrate inserted into a copper or copper alloy cannister, which is subsequently extruded into filaments.
  • a substance which acts as a barrier to substantially prevent further diffusion from the metal layer during subsequent processing, eg. niobium or silver, may be placed upon the superconducting inorganic compound prior to deposition of the metal layer.
  • the substrate may be metallic eg. silver, gold, titanium, copper or molybdenum or an alloy or it may be a ceramic.
  • the substrate may be fully dense or it may be porous.
  • the substrate may be copper cored.
  • the substrate may be silver or silver-coated.
  • a process for manufacturing a superconducting inorganic compound on a substrate where such substrate is a metal such as copper or a copper alloy, said process including the steps of roughening the surface of the substrate eg. by immersion in ammonium persulphate, coating the roughened surface of the substrate with a suspension of a plurality of particles of different metals, such as yttrium or barium, and subsequently heating the coated substrate in an atmosphere and at a temperature which results in the oxidisation of the metal substrate and the metal particles so as to form a superconducting inorganic compound.
  • the surface of the substrate may be preheated in an oxygen-containing atmosphere prior to coating, such that where the metal substrate is eg. copper, a layer of copper oxide (CuO) is formed on the surface of the copper.
  • a layer of copper oxide (CuO) is formed on the surface of the copper.
  • Such heating may take place in air for example at a temperature of 200-300°C.
  • a copper oxide (CuO) layer may be formed on a copper substrate by electrolytic means prior to the coating step.
  • fibres eg. of alumina or zirconia or silicon carbide may be incorporated in one or more of the coatings.
  • carbon-containing compounds such as oxalates or citrates may be incorporated in the coatings.
  • Flake copper or silver powder may also or alternatively be incorporated in one or more coatings.
  • the products of the processes according to the invention have properties which make them useable as superconducting materials.
  • a wire or tape it may be incorporated in or onto the surface of a carrier such as a disk for storing data in electronic form.
  • the coated substrate may after subsequent processing be useful as a contact capable of carrying high current flows or for passing pulsed currents.
  • a platelet shaped YBa2Cu3O7 ceramic powder made by the citrate route was milled to give a particle size of between 1 and 6 microns.
  • a suspension was prepared of the powder in isopropyl alcohol and nitromethane. Zein was added as an activator and a small amount of aluminium nitrate was also added.
  • the quantities of the suspension were as follows YBa2Cu3O7 ceramic 10 gms Zein 0.2 gm Nitromethane 50 mls Isopropyl alcohol 50 mls Aluminium nitrate 0.005 gm
  • the substrate was a roughened silver wire positioned between two platinised titanium anodes, the potential of the wire being negative (cathodic) relative to the anodes, the assembly being immersed in the suspension. Up to 50 volts constant voltage was applied between the anodes and the cathode, with a cell current typically of about 10 mA being measured.
  • the coated substrate was removed from the assembly, washed in isopropyl alcohol and dried in air at 120 °C.
  • the coated substrate was then baked in air at 550 °C to remove organic matter and subsequently sintered at 930 °C in oxygen/air and finally annealed in oxygen at 450 °C.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Superconductor Devices And Manufacturing Methods Thereof (AREA)
  • Oxygen, Ozone, And Oxides In General (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)

Abstract

Processes for manufacturing high Tc superconductors by electrophoretic deposition onto a substrate or by coating onto the substrate a plurality of components in solution or suspension and subsequent heat treatment. The substrate is preferably conducting and may be silver and the coating or deposition may be further coated with a layer of metal or resin.

Description

  • This invention relates to processes for the manufacture of superconducting inorganic compounds and the products of such processes.
  • It is now well established that certain ceramic compositions will become superconducting when held at sufficiently low temperature. More recently a rare earth containing material, YBa₂Cu₃O7-x, has been shown to become superconducting at liquid nitrogen temperature as opposed to much lower temperatures essential for inducing superconductivity in metals, alloys and intermetallics previously used. Such novel ceramic composition material has become known as high Tc ceramic. This patent application relates especially, but not exclusively, to the formation of 'thick' film devices and to wire/tape formation. The technique is applicable to the formation of ceramic compositions other than YBa₂Cu₃O7-x, for example the BiSrCaCuO formulation.
  • According to one aspect of the invention we provide a process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, depositing on said surface particles of a superconducting inorganic compound from a suspension of such particles by electrophoresis.
  • The superconducting inorganic compound may subsequently be covered with a resin or varnish or a metal layer such as copper or silver may be deposited thereon. For example, pure copper may be deposited and then coated by a resin or varnish. Alternatively, pure copper may be deposited on the superconducting inorganic compound, and the product together with its substrate may then be inserted into a copper or copper alloy cannister, which is subsequently extruded into filaments. A substance which acts as a barrier to substantially prevent further diffusion from the metal layer during subsequent processing may be placed upon the superconducting inorganic compound prior to deposition of the metal layer.
  • The superconducting inorganic compound is typically an oxide of the form AwBxOy where A and B represent elements of which at least one is a metallic element and the subscripts w x and y are numerals denoting the empirical atomic proportions of the compound conducting oxide. There may be additional metallic elements eg. Cz etc present in the compound conducting oxide.
  • Such compound conducting oxides may be of the form ABO₃, ABO₄ or A₂BO₄ or A₂BO(4-y). Typical elements involved in the formation of these superconducting oxides are yttrium, barium, bismuth, lanthanum, strontium and copper. The present invention is not limited to these elements: the yttrium may be replaced by other rare earth elements, the barium by other alkali elements, and the entire compound may not be a cuprate, but a bismuthate or other compound. The deposited layer will be in a combined rather than elemental state, and typically would be an oxide.
  • The metallic layer, which could be copper or a copper alloy, may be deposited immediately following the removal of unattached suspension or contaminants eg. by washing or other cleaning process, from the oxide coated substrate. The substrate is typically an electrically conducting material such as a metal eg. silver, copper or a copper alloy, or molybdenum or titanium or an alloy of one of these. It may be coated by a barrier film prior to the deposition stage.
  • Alternatively, a metallic layer may be deposited after an intermediate treatment such as a heat-treatment of the coated substrate.
  • According to another aspect of the invention we provide a process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, depositing on said surface particles of a plurality of different compounds such as oxides or carbonates or a mixture of oxides and carbonates from a suspension of such particles by electrophoresis. Such compounds may include organo-metallic substances.
  • The deposit may subsequently be covered with a resin or varnish or a metal layer may be deposited thereon. For example, pure copper may be deposited and then coated by a resin or varnish. Alternatively, pure copper may be deposited on the existing deposit, and the resulting product together with its substrate inserted into a copper or copper alloy cannister, which is subsequently extruded into filaments. A substance which acts as a barrier to substantially prevent further diffusion from the metallayer during subsequent processing may be placed upon the existing deposit prior to deposition of the metal layer. Preferably prior to the deposit of any layer of resin or metal, the oxide/carbonate coated substrate may be heat-treated in an oxidising atmosphere at elevated temperatures sufficient to cause said particles to chemically react together to form a superconducting inorganic compound. The oxides and/or carbonates will typically include at least one metallic compound. The oxide/carbonate coated substrate could be cleaned in a manner referred to above prior to the heat treatment.
  • The substrate may be metallic eg. silver, gold, titanium, copper or molybdenum or it may be an electrically conducting ceramic or a carbon-containing substance. The substrate may be silver-coated or platinum-coated. The substrate may be fully dense or it may be porous. The substrate may be copper cored. In either aspect of the invention the substrate may be in the form of a strip, tape or wire, tube, plate or disc. The surface of the substrate may be plane, curved, corrugated or stepped. For example the substrate may be a wire with multiple re-entrant portions eg. star-shaped when viewed in cross-section. Alternatively the substrate may be a substantially plane disc with micro-grooves on its surface.
  • After the depositing of the metallic layer the oxide-coated substrate may be mechanically worked eg. by drawing, extruding or rolling, so as to consolidate the superconducting compound. Such mechanical working may take place at ambient temperature or at an elevated temperature. The material may also be subject to heat treatment. Further mechanical working and heat treatment may also be necessary.
  • A bundle of strips, tapes or wires so formed may then be bundled together in an evacuated metallic cannister eg. of copper or copper alloy or silver-coated copper or alloy, and such container and its contents co-extruded or drawn in multiple stages to produce a fine elongate product containing a plurality of filaments of conducting oxide material. An oxygen-evolving compound or substance eg. silver oxide may be incorporated with the bundle of strips etc on their admission to the cannister.
  • An electromagnetic field eg a magnetic field, may be applied during the electrophoretic deposition stage to encourage the deposited particles to take up a particular orientation.
  • In all aspects of the invention fibrous particles such as ceramic fibres, alumina or zirconia fibres or silicon carbide fibres may be incorporated into the suspension and electrophoretically deposited onto the surface of the substrate. The particles being deposited may be substantially rounded, or may be acicular or platelet-type in shape. Sizes of particles deposited are typically up to a few microns in size, but larger sizes can be accommodated by attention to the viscosity of the electrophoreting bath.
  • The roughening of the surface of the substrate may be carried out by etching eg. with copper by ammonium persulphate and/or ferric sulphate, or in the case of molybdenum by pickling in hydrochloric acid.
  • The suspension may be dispersed in an electrolyte which includes nitromethane and isopropyl alcohol and possibly additionally zein and aluminium nitrate as necessary for efficient electrophoresis.
  • According to a still further aspect of the invention we provide a process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, applying a fluid coating onto said surface, the coating comprising a plurality of components in suspension and/or in solution in a liquid medium. Said components may comprise metallic compounds such as a chloride, sulphate or nitrate or a citrate, acetate and other salts. The coated substrate is typically heated to a temperature sufficient to cause decomposition of said components and the formation of a surface film of superconducting inorganic compound incorporating each of the elements present.
  • A plurality of successive coatings may be applied, each of said successive coatings containing identical components, or at least some of each of said successive coatings containing differing components. Where a solution is applied to the substrate, it may comprise metal compounds dissolved in an organic base, such as so-called "organo-metallic paints".
  • According to another aspect of the invention we provide a process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, applying a coating on the said surface, the coating comprising a suspension of particles of a superconducting inorganic compound suspended in a liquid medium. Successive coatings may be built up one upon the other. The coated substrate may then be given a heat treatment in e.g. an oxygen-containing atmosphere such as pure oxygen at atmospheric, sub-atmospheric or elevated pressure. The average particle size of the superconducting inorganic compound may be less than one micron.
  • A drying step may be incorporated into the processes according to the invention following the application of the or each coating. Such drying step may be carried out in air and is completed when the liquid medium is substantially evaporated. Relatively volatile dispersion medium is typically selected for example an alcohol.
  • Where heating is used, this may take place in an oxygen containing atmosphere. Heating is typically carried out between a temperature of 400-500°C. The coating may be applied to a cool substrate which is then heated to change the deposit to the desired composition. Alternatively the coating can wholly or in part be applied eg. by spraying, onto a heated substrate so as to effect decompositioned changes at a fast and homogeneous rate.
  • Where multiple coatings may be applied to the substrate, each such coating may in turn be dried to remove the liquid medium before the application of the next coating. The superconducting inorganic compound may subsequently be covered with a resin or varnish or a metal layer may be deposited thereon. For example, pure copper may be deposited, or silver deposited by thermal decomposition technique, and the copper or silver then coated by a resin or varnish. Alternatively, pure copper may be deposited on the superconducting inorganic compound, and together with its substrate inserted into a copper or copper alloy cannister, which is subsequently extruded into filaments. A substance which acts as a barrier to substantially prevent further diffusion from the metal layer during subsequent processing, eg. niobium or silver, may be placed upon the superconducting inorganic compound prior to deposition of the metal layer.
  • The substrate may be metallic eg. silver, gold, titanium, copper or molybdenum or an alloy or it may be a ceramic. The substrate may be fully dense or it may be porous. The substrate may be copper cored. The substrate may be silver or silver-coated.
  • According to a still further aspect of the invention we provide a process for manufacturing a superconducting inorganic compound on a substrate, where such substrate is a metal such as copper or a copper alloy, said process including the steps of roughening the surface of the substrate eg. by immersion in ammonium persulphate, coating the roughened surface of the substrate with a suspension of a plurality of particles of different metals, such as yttrium or barium, and subsequently heating the coated substrate in an atmosphere and at a temperature which results in the oxidisation of the metal substrate and the metal particles so as to form a superconducting inorganic compound. In this latest aspect of the invention, the surface of the substrate may be preheated in an oxygen-containing atmosphere prior to coating, such that where the metal substrate is eg. copper, a layer of copper oxide (CuO) is formed on the surface of the copper. Such heating may take place in air for example at a temperature of 200-300°C. Alternatively, a copper oxide (CuO) layer may be formed on a copper substrate by electrolytic means prior to the coating step.
  • In all aspects of the invention, fibres eg. of alumina or zirconia or silicon carbide may be incorporated in one or more of the coatings. Similarly, carbon-containing compounds such as oxalates or citrates may be incorporated in the coatings. Flake copper or silver powder may also or alternatively be incorporated in one or more coatings.
  • The products of the processes according to the invention have properties which make them useable as superconducting materials. As a wire or tape it may be incorporated in or onto the surface of a carrier such as a disk for storing data in electronic form. Alternatively, the coated substrate may after subsequent processing be useful as a contact capable of carrying high current flows or for passing pulsed currents.
  • One embodiment of the invention will now be described, by way of example only.
  • A platelet shaped YBa₂Cu₃O₇ ceramic powder made by the citrate route was milled to give a particle size of between 1 and 6 microns.
  • A suspension was prepared of the powder in isopropyl alcohol and nitromethane. Zein was added as an activator and a small amount of aluminium nitrate was also added.
  • The quantities of the suspension were as follows
        YBa₂Cu₃O₇ ceramic 10 gms
        Zein 0.2 gm
        Nitromethane 50 mls
        Isopropyl alcohol 50 mls
        Aluminium nitrate 0.005 gm
  • The substrate was a roughened silver wire positioned between two platinised titanium anodes, the potential of the wire being negative (cathodic) relative to the anodes, the assembly being immersed in the suspension. Up to 50 volts constant voltage was applied between the anodes and the cathode, with a cell current typically of about 10 mA being measured.
  • Between applied voltages of 0-50 volts there was a straight-line relationship between the quantity of electrophoretic deposition in gm/cm² and voltage. The quantity of deposition at constant voltage was also initially a straight-line increasing relationship but this eventually fell off after about 4 minutes.
  • For a deposition at 30 volts over 2 minutes, the coated substrate was removed from the assembly, washed in isopropyl alcohol and dried in air at 120 °C. The coated substrate was then baked in air at 550 °C to remove organic matter and subsequently sintered at 930 °C in oxygen/air and finally annealed in oxygen at 450 °C.

Claims (12)

1. A process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, depositing on said surface particles of a superconducting inorganic compound from a suspension of such particles by electrophoresis.
2. A process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, depositing on said surface particles of a plurality of different compounds such as oxides or carbonates or a mixture of oxides and carbonates from a suspension of such particles by electrophoresis.
3. A process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, applying a coating onto said surface, the coating comprising a plurality of components in suspension and/or in solution in a liquid medium.
4. A process for manufacturing a superconducting inorganic compound on a substrate including the steps of roughening a surface of the substrate, applying a coating on the said surface, the coating comprising a suspension of particles of a superconducting inorganic compound suspended in a liquid medium.
5. A process according to any preceding claim in which the superconducting inorganic compound is subsequently covered with a resin or varnish or a layer of metal.
6. A process according to Claim 5 in which a substance which acts as a barrier to substantially prevent further diffusion from the metal layer during subsequent processing is placed upon the superconducting inorganic compound prior to deposition of the metal layer.
7. A process as claimed in any preceding claim in which the substrate is silver or silver coated or platinum coated.
8. A process as claimed in any of Claims 1 to 6 in which the substrate is an electrically conducting ceramic.
9. A process as claimed in Claim 5 in which after deposition of the metallic layer, the substrate coated with the inorganic compound is mechanically worked.
10. A process as claimed in Claim 4 in which the coated substrate is subsequently provided with a heat treatment in an oxygen-containing atmosphere.
11. A process in which the particles being electrophoretically deposited are rounded in shape, acicular or platelet type.
12. A process in which the electrophoresis is carried out under the influence of a strong magnetic field.
EP19880201071 1987-06-04 1988-05-30 Processes for the manufacture of superconducting inorganic compounds and the products of such processes Withdrawn EP0293981A3 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB878713121A GB8713121D0 (en) 1987-06-04 1987-06-04 Superconducting inorganic compounds
GB8713122 1987-06-04
GB878713122A GB8713122D0 (en) 1987-06-04 1987-06-04 Superconducting inorganic compounds
GB8713121 1987-06-04

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Publication Number Publication Date
EP0293981A2 true EP0293981A2 (en) 1988-12-07
EP0293981A3 EP0293981A3 (en) 1990-10-10

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EP (1) EP0293981A3 (en)
JP (1) JPS6465299A (en)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0300646A2 (en) * 1987-07-22 1989-01-25 Chloride Silent Power Limited Preparing superconducting ceramic materials
EP0301962A2 (en) * 1987-07-27 1989-02-01 Sumitomo Electric Industries Limited A superconducting thin film and a method for preparing the same
EP0350143A1 (en) * 1988-07-06 1990-01-10 Ametek, Inc. Formation of superconducting articles by electrodeposition
EP0375276A2 (en) * 1988-12-22 1990-06-27 General Atomics Apparatus for manufacturing an elongated superconductor
EP0376060A1 (en) * 1988-12-24 1990-07-04 Asea Brown Boveri Aktiengesellschaft Process for manufacturing a super conductor
EP0382194A1 (en) * 1989-02-08 1990-08-16 Siemens Aktiengesellschaft Electrophoretic deposition of a superconducting coating under the influence of an external magnetic field
FR2647266A1 (en) * 1989-05-17 1990-11-23 Ecole Cle Arts Manufactures Electrical or electronic circuit element including a super-conductor to which conducting elements are fixed
DE3930252A1 (en) * 1989-09-11 1991-03-28 Licentia Gmbh Ceramic superconductor parts made with higher current density - by using magnetic field to orient crystallites during filling of forms before compression at elevated temp.
GB2236326A (en) * 1989-08-31 1991-04-03 Gold Star Co Making superconductive components by electrodeposition
EP0476878A2 (en) * 1990-09-21 1992-03-25 General Atomics Process and apparatus for fabrication of silver coated high temperature ceramic superconductor fiber with metal substrate
EP0476881A2 (en) * 1990-09-21 1992-03-25 General Atomics Anhydrous electrophoretic silver coating technique
EP0476879A2 (en) * 1990-09-21 1992-03-25 General Atomics Apparatus and method for manufacturing an improved ceramic superconductor coated metal fiber
EP0482777A2 (en) * 1990-10-01 1992-04-29 Sharp Kabushiki Kaisha Method for fabricating oxide superconducting coatings
DE19535262A1 (en) * 1995-09-22 1997-03-27 Josef Dr Heyes Electrophoretic prodn. of superconducting wires
WO2007148642A1 (en) 2006-06-19 2007-12-27 Jgc Catalysts And Chemicals Ltd. Method of forming metal oxide microparticle layer on conductive substratum

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JPS6441122A (en) * 1987-08-06 1989-02-13 Mitsubishi Cable Ind Ltd Manufacture of superconductor of ceramic-based superconductive material
JP2595273B2 (en) * 1987-12-25 1997-04-02 株式会社フジクラ Method of forming superconductor layer

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Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0300646A2 (en) * 1987-07-22 1989-01-25 Chloride Silent Power Limited Preparing superconducting ceramic materials
EP0300646A3 (en) * 1987-07-22 1989-09-06 Chloride Silent Power Limited Preparing superconducting ceramic materials
EP0301962A2 (en) * 1987-07-27 1989-02-01 Sumitomo Electric Industries Limited A superconducting thin film and a method for preparing the same
EP0301962A3 (en) * 1987-07-27 1990-02-07 Sumitomo Electric Industries Limited A superconducting thin film and a method for preparing the same
EP0350143A1 (en) * 1988-07-06 1990-01-10 Ametek, Inc. Formation of superconducting articles by electrodeposition
EP0375276A2 (en) * 1988-12-22 1990-06-27 General Atomics Apparatus for manufacturing an elongated superconductor
EP0375276A3 (en) * 1988-12-22 1992-01-02 General Atomics Apparatus for manufacturing an elongated superconductor
EP0376060A1 (en) * 1988-12-24 1990-07-04 Asea Brown Boveri Aktiengesellschaft Process for manufacturing a super conductor
EP0382194A1 (en) * 1989-02-08 1990-08-16 Siemens Aktiengesellschaft Electrophoretic deposition of a superconducting coating under the influence of an external magnetic field
FR2647266A1 (en) * 1989-05-17 1990-11-23 Ecole Cle Arts Manufactures Electrical or electronic circuit element including a super-conductor to which conducting elements are fixed
GB2236326A (en) * 1989-08-31 1991-04-03 Gold Star Co Making superconductive components by electrodeposition
DE3930252A1 (en) * 1989-09-11 1991-03-28 Licentia Gmbh Ceramic superconductor parts made with higher current density - by using magnetic field to orient crystallites during filling of forms before compression at elevated temp.
EP0476878A2 (en) * 1990-09-21 1992-03-25 General Atomics Process and apparatus for fabrication of silver coated high temperature ceramic superconductor fiber with metal substrate
EP0476879A3 (en) * 1990-09-21 1992-08-05 General Atomics Apparatus and method for manufacturing an improved ceramic superconductor coated metal fiber
EP0476879A2 (en) * 1990-09-21 1992-03-25 General Atomics Apparatus and method for manufacturing an improved ceramic superconductor coated metal fiber
EP0476881A2 (en) * 1990-09-21 1992-03-25 General Atomics Anhydrous electrophoretic silver coating technique
EP0476878A3 (en) * 1990-09-21 1992-07-22 General Atomics Process and apparatus for fabrication of silver coated high temperature ceramic superconductor fiber with metal substrate
EP0476881A3 (en) * 1990-09-21 1992-08-05 General Atomics Anhydrous electrophoretic silver coating technique
EP0482777A3 (en) * 1990-10-01 1992-08-05 Sharp Kabushiki Kaisha Method for fabricating oxide superconducting coatings
EP0482777A2 (en) * 1990-10-01 1992-04-29 Sharp Kabushiki Kaisha Method for fabricating oxide superconducting coatings
US5219828A (en) * 1990-10-01 1993-06-15 Sharp Kabushiki Kaisha Method for fabricating oxide superconducting coatings
US5318951A (en) * 1990-10-01 1994-06-07 Sharp Kabushiki Kaisha Method for fabricating oxide superconducting coatings
DE19535262A1 (en) * 1995-09-22 1997-03-27 Josef Dr Heyes Electrophoretic prodn. of superconducting wires
WO2007148642A1 (en) 2006-06-19 2007-12-27 Jgc Catalysts And Chemicals Ltd. Method of forming metal oxide microparticle layer on conductive substratum
EP2045369A1 (en) * 2006-06-19 2009-04-08 JGC Catalysts and Chemicals Ltd. Method of forming metal oxide microparticle layer on conductive substratum
US7901742B2 (en) 2006-06-19 2011-03-08 Jgc Catalysts And Chemicals Ltd. Method for forming metal oxide fine particle layer on conductive substrate
EP2045369A4 (en) * 2006-06-19 2011-04-27 Jgc Catalysts & Chemicals Ltd Method of forming metal oxide microparticle layer on conductive substratum

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